I had also COMPLETELY forgot that Sid had another daughter, Annie. She could've been an interesting character to bring on down the line, particularly given what happened to her father nearly a year later.

It was a huge, huge, HUGE miss on the show's part not keeping Karen Allen on as Annie. She was one of the best things about the pilot -- possibly even the best thing. One of the scenes that sticks out to me the most (not just of the pilot, but of the series as a whole) is when Annie crashes the Averys' backyard barbecue and starts waxing poetic about rolling around naked in the sand on the beach and embarrassing the more-reserved Laura.